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21.
Parche S Thomae AW Schlicht M Titgemeyer F 《Journal of molecular microbiology and biotechnology》2001,3(3):415-422
We have surveyed the publicly available genome sequence of Corynebacterium diphtheriae (www.sanger.ac.uk) to identify components of the phosphotransferase system (PTS), which plays a central role in carbon metabolism in many bacteria. Three gene loci were found to contain putative pts genes. These comprise: (i) the genes of the general phosphotransferases enzyme I (ptsI) and HPr (ptsH), a fructose-specific enzyme IIABC permease (fruA), and a fructose 1-phosphate kinase (fruK); (ii) a gene that encodes an enzyme IIAB of the fructose/mannitol family, and a novel HPr-like gene, ptsF, that encodes an HPr domain fused to a domain of unknown function; (iii) and a gene for a glucose-specific enzyme IIBCA (ptsG). A search for genes that may be putative PTS-targets or that may operate in general carbon regulation revealed a possible regulatory gene encoding an antiterminator protein downstream from ptsG. Furthermore, genes were detected encoding glycerol kinase, glucose kinase, and a homologue of the global activator of carbon catabolite repression in Escherichia coli, CAP. The possible significance of these observations in carbon metabolism and the novel features of the detected genes are discussed. 相似文献
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Torsional stress induces left-handed helical stretches in DNA of natural base sequence: circular dichroism and antibody binding 总被引:15,自引:6,他引:9 下载免费PDF全文
Above a threshold of torsional stress, the c.d. spectrum of covalently closed circular DNA of natural base sequence acquires a Z-like contribution and antibodies raised against Z-DNA are bound. Mapping of the antibody binding sites by electron microscopy reveals sites which correlate with stretches enriched in alternating purine-pyrimidine sequences and GC base pairs. 相似文献
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Pylypenko O Rak A Durek T Kushnir S Dursina BE Thomae NH Constantinescu AT Brunsveld L Watzke A Waldmann H Goody RS Alexandrov K 《The EMBO journal》2006,25(1):13-23
In eukaryotic cells Rab/Ypt GTPases represent a family of key membrane traffic controllers that associate with their targeted membranes via C-terminally conjugated geranylgeranyl groups. GDP dissociation inhibitor (GDI) is a general and essential regulator of Rab recycling that extracts prenylated Rab proteins from membranes at the end of their cycle of activity and facilitates their delivery to the donor membranes. Here, we present the structure of a complex between GDI and a doubly prenylated Rab protein. We show that one geranylgeranyl residue is deeply buried in a hydrophobic pocket formed by domain II of GDI, whereas the other lipid is more exposed to solvent and is skewed across several atoms of the first moiety. Based on structural information and biophysical measurements, we propose mechanistic and thermodynamic models for GDI and Rab escort protein-mediated interaction of RabGTPase with intracellular membranes. 相似文献
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Yiannis P. Ninios Kalliope E. Sekeri-Pataryas Thomae G. Sourlingas 《Apoptosis : an international journal on programmed cell death》2010,15(2):128-138
A major hallmark of the terminal stages of apoptosis is the internucleosomal DNA fragmentation. The endonuclease responsible
for this type of DNA degradation is the DNA fragmentation factor (DFF). DFF is a complex of the endonuclease DFF40 and its
chaperone/inhibitor, DFF45. In vitro work has shown that histone H1 and HMGB1/2 recruit/target DFF40 to the internucleosomal
linker regions of chromatin and that histone H1 directly interacts with DFF40 conferring DNA binding ability and enhancing
its nuclease activity. The histone H1 family is comprised of many subtypes, which recent work has shown may have distinct
roles in chromatin function. Thus we studied the binding association of DFF40 with specific H1 subtypes and whether these
binding associations are altered after the induction of apoptosis in an in vivo cellular context. The apoptotic agent used
in this study is the histone deacetylase inhibitor, trichostatin A (TSA). We separated the insoluble chromatin-enriched fraction
from the soluble nuclear fraction of the NB4 leukemic cell line. Using MNase digestion, we provide evidence which strongly
suggests that the heterodimer, DFF40-DFF45, is localized to the chromatin fraction under apoptotic as well as non-apoptotic
conditions. Moreover, we present results that show that DFF40 interacts with the all H1 subtypes used in this study, but preferentially
interacts with specific H1 subtypes after the induction of apoptosis by TSA. These results illustrate for the first time the
association of DFF40 with individual H1 subtypes, under a specific apoptotic stimulus in an in vivo cellular context. 相似文献
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Andrea Lukacs Andreas W. Thomae Peter Krueger Tamas Schauer Anuroop V. Venkatasubramani Natalia Y. Kochanova Wasim Aftab Rupam Choudhury Ignasi Forne Axel Imhof 《PLoS genetics》2021,17(8)
Postzygotic isolation by genomic conflict is a major cause for the formation of species. Despite its importance, the molecular mechanisms that result in the lethality of interspecies hybrids are still largely unclear. The genus Drosophila, which contains over 1600 different species, is one of the best characterized model systems to study these questions. We showed in the past that the expression levels of the two hybrid incompatibility factors Hmr and Lhr diverged in the two closely related Drosophila species, D. melanogaster and D. simulans, resulting in an increased level of both proteins in interspecies hybrids. The overexpression of the two proteins also leads to mitotic defects, a misregulation in the expression of transposable elements and decreased fertility in pure species. In this work, we describe a distinct six subunit protein complex containing HMR and LHR and analyse the effect of Hmr mutations on complex integrity and function. Our experiments suggest that HMR needs to bring together components of centromeric and pericentromeric chromatin to fulfil its physiological function and to cause hybrid male lethality. 相似文献
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Cynthia Kuhn Misha Johnson Alex Thomae Brooke Luo Sidney A Simon Guiying Zhou Q. David Walker 《Hormones and behavior》2010,58(1):122-137
Adolescence is the developmental epoch during which children become adults—intellectually, physically, hormonally and socially. Brain development in critical areas is ongoing. Adolescents are risk-taking and novelty-seeking and they weigh positive experiences more heavily and negative experiences less than adults. This inherent behavioral bias can lead to risky behaviors like drug taking. Most drug addictions start during adolescence and early drug-taking is associated with an increased rate of drug abuse and dependence.The hormonal changes of puberty contribute to physical, emotional, intellectual and social changes during adolescence. These hormonal events do not just cause maturation of reproductive function and the emergence of secondary sex characteristics. They contribute to the appearance of sex differences in non-reproductive behaviors as well. Sex differences in drug use behaviors are among the latter. The male predominance in overall drug use appears by the end of adolescence, while girls develop the rapid progression from first use to dependence (telescoping) that represent a female-biased vulnerability. Sex differences in many behaviors including drug use have been attributed to social and cultural factors. A narrowing gap in drug use between adolescent boys and girls supports this thesis. However, some sex differences in addiction vulnerability reflect biologic differences in brain circuits involved in addiction. The purpose of this review is to summarize the contribution of sex differences in the function of ascending dopamine systems that are critical to reinforcement, to briefly summarize the behavioral, neurochemical and anatomical changes in brain dopaminergic functions related to addiction that occur during adolescence and to present new findings about the emergence of sex differences in dopaminergic function during adolescence. 相似文献
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Detecting recombination from gene trees 总被引:28,自引:10,他引:18
In this article, a method is proposed for detecting recombination in the
sequences of a gene from a set of closely related organisms. The method,
the Homoplasy Test, is appropriate when the sequences are rather similar,
differing by 1%-5% of nucleotides. It is effective in detecting relatively
frequent recombination between a set of rather similar strains, in contrast
to previous methods which detect rare or unique transfers between more
distant strains. It is based on the fact that, if there is no recombination
and if no repeated mutations have occurred (homoplasy), then the number of
polymorphic sites, v, is equal to the number of steps, t, in a
most-parsimonious tree. If the number of "apparent homoplasies" in the
most-parsimonious tree, h = t-v, is greater than zero, then either
homoplasies have occurred by mutation or there has been recombination. An
estimate of the distribution of h expected on the null hypothesis of no
recombination depends on Se, the "effective site number," defined as
follows: if ps is the probability that two independent substitutions in the
gene occur at the same site, then Se = 1/ps. Se can be estimated if a
suitable outgroup is available. The Homoplasy Test is applied to three
bacterial genes and to simulated gene trees with varying amounts of
recombination. Methods of estimating the rate, as opposed to the
occurrence, of recombination are discussed.
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